Willow flowers

Willow, I was told by a bee-keeper last year, is the earliest tree to flower. Flowers of all kinds provide bees with nectar from which they make honey, and with pollen which is the only protein source for bees. Very little nectar is collected from willow, but the pollen is an important source of protein early in the year.
Our area of young woodland contains many volunteer willow plants which we used to consider as weeds to be removed, but now let grow for the bees, provided they are not competing with the planted species.